Communications cables can be used to direct data and electrical power among the nodes of a communications network. For example, communications cables can be used to transmit and receive data (e.g., among network computers), voice, and control signals (e.g., security signals, fire alarms, temperature control signals, etc.) among the nodes of a communications network.
Communications cables often extend through various infrastructures such as modern residential or office buildings. These cables can be used for a wide range of applications, for example to provide data transmission between computers, voice communications, and control signals (e.g., security signals, fire alarms, temperature control signals, etc.). Such cables can extend throughout buildings, and frequently even through the spaces in the walls, above floors, or in dropped ceilings. Such spaces (e.g., spaces above floors or below ceilings) are commonly referred to as the “plenum area.” The plenum area can often include ventilation system components, such as pipes used for directing cool or warm air through buildings and their return air exchange pipes. Communications and electrical cables included in the plenum area are governed by provisions of the National Electric Code (“NEC”).
In the event of an electrical fire, flame and potentially hazardous smoke can travel through a plenum area by burning cables (e.g., communications and electrical cables) disposed in that area. Accordingly, building designers often take various precautions to resist the spread of flame (in case of an outbreak of fire) and the generation of and spread of smoke throughout buildings. Further, communications and electrical cables are often designed to protect against loss of life, and minimize costs associated with destruction of cables, electrical components, and other equipment. As detailed in U.S. patent application Ser. No. 14/970,672 and U.S. Pat. No. 6,639,152, the entire teachings of which are incorporated herein by reference, various standards govern the design and use of cables in residential and commercial buildings. These standards often impose stringent requirements on cables used in residential and commercial buildings. For example, in plenum applications for voice and data transmission, electrical conductors and cables should exhibit low smoke evolution, low flame spread, and favorable electrical properties to pass the stringent requirements of copper data cables. Separators, cable jackets, insulations, buffer tubes and blown fiber tubing used in communications cables must also satisfy the standards for flammability and smoke generation. Accordingly, there is a need for an improved communications cable.
The term “transmission modem,” as used herein, refers to any modem known and available in the art that can carry data and/or electrical power. The term “about,” as used herein, denotes a variation of at most 5%, e.g., of a numerical value.